Sunday, January 29, 2012

Native Vines Grow on You

While I have a number of native vines in the natural area of my yard, it was several years before I decided to add new ones to the landscaped areas.  Perhaps I was a little afraid that a vine would be too aggressive.  Eventually, their beauty overcame any fear – I wanted to see the large and colorful blooms of crossvine (Bignonia capreolata), to support hummingbirds with the red tubal flowers of our native honeysuckle (Lonicera sempervirens), to delight my visitors with the delicate bells of our native leather-flower (Clematis viorna), and to be wowed by the springtime show of Carolina jessamine (Gelsemium sempervirens).

Pale passionflower, Passiflora lutea

I also learned more about how they support native wildlife: from hummingbirds and insect pollinators to birds that eat their berries and insects that feed on their foliage.  I was inspired by Doug Tallamy’s story about growing Virginia creeper (Parthenocissus quinquefolia) just so that he could observe the larvae of the Pandorus sphinx moth (Eumorpha pandorus).  I decided that planting more vines would increase the diversity of host plants to support insects that feed on foliage.

The first thing to consider about vines – as it would be for any kind of plant – is how they grow.  For vines that means considering HOW they climb.  Each vine has its own way of climbing:

Twine – a vine that twines will physically wrap itself around small branches or trunks of other plants or around supports provided by the gardener.  Trying to grow such a vine next to a solid wall without any twine-able support would be an exercise in futility.  Honeysuckle (Lonicera spp.) and Carolina jessamine (Gelsemium sempervirens) are two that twine.

Lonicera sempervirens

Cling – a vine that clings will physically attach itself to a wall, a fence or another plant.  This same vine may cause damage to structures when you try to detach it!  Virginia creeper (Parthenocissus quinquefolia) and wood vamp (Decumaria barbara) are both clingers; the creeper clings with little adhesive discs while the vamp clings with aerial roots.

Parthenocissus quinquefolia

Decumaria barbara

Tendril – a vine with tendrils anchors itself to another plant or thin support via curly tendrils.  Vines like grape (Vitis spp.) have very thick tendrils while clematis (Clematis spp.) have thin tendrils.

A grape latches onto a nearby oak sapling

Ramble – a vine that rambles is really a shrub with long branches and usually requires physical support (e.g., tying it to an arbor or structure) initially.  Roses are ramblers.

Knowing the difference in how they grow helps me quickly identify two evergreen vines in the wild: Gelsemium sempervirens (a twiner) and Bignonia capreolata (a clinger).  But as I said, the real reason to know is so that the environment that you place them in will be one where they can thrive.  Unfortunately, I speak from experience!

Passiflora lutea waltzing through my plumleaf azalea

If you select a vine that twines or has tendrils, be sure to provide some support for the vine or it will twine all over itself and make a bit of a mess.  You can use a fence with slender rails, a metal trellis, or you can even supplement the area with sturdy twine or rope stretched out in a vertical fashion.  I've seen the native coral honeysuckle (Lonicera sempervirens) twine throughout a chain link fence beautifully - the fence was almost obscured.  Of course you can let the vine scramble over other shrubs or small trees if you like.  Passionflower (Passiflora spp.) is perennial but not woody so it takes a different path through my shrubs every year as it grows.

If you select a vine that clings, be sure to consider where it is going to cling.  Allowing a vine to cling to a wooden house is not recommended as it could collect and hold moisture, permitting some rot over time.  But a clinging vine can happily climb up a tree if you like.  I recently trained Virginia creeper to climb up my store-bought landscape blocks.  I'm looking forward to having it improve the looks of those boring concrete blocks.

That's all there is to understand - now you can consider what native vines you might like to grow!  Most vines do love sun.  They will tolerate some shade but you may not get the amount of blooms that you want. Here are some of the ones that I would recommend:

Crossvine - Bignonia capreolata: clings, evergreen, large and colorful trumpet-shaped flowers in spring.
Coral honeysuckle - Lonicera sempervirens: twines, semi-evergreen, bright red flowers for hummingbirds in summer.
Carolina jessamine - Gelsemium sempervirens: twines, evergreen, early flowering spring vine, can be aggressive.
Passionflower - Passiflora incarnata (purple) or P. lutea (yellow): tendrils, host plant for Gulf Fritillary butterfly.
Leather-flower clematis - Clematis viorna: tendrils, unusual flowers. Good reference here.
Virgin's bower clematis - Clematis virginiana: tendrils, white flowers, can be aggressive.
Virginia creeper Parthenocissus quinquefolia: clings, decorative blue berries, outstanding fall color.
Wood vamp - Decumaria barbara: clings, semi-evergreen in protected areas; also known as climbing hydrangea.
Rose - Rosa setigera: rambles, has rose hips for wildlife.
Wisteria - Wisteria frutescens: twines, blooms at a young age, not as aggressive as the Asian species, but also not very fragrant. Generally sold as a cultivar like 'Amethyst Falls'.

Cultivars are available now for many native vines, and I've heard that even some of the trumpet creeper cultivars (Campsis radicans) are not as aggressive as the species.  I'll believe that when I see it - that's a vine that really should just be grown on telephone poles!

Parthenocissus quinquefolia
Passiflora incarnata

Campsis radicans

Lonicera sempervirens

Sunday, January 22, 2012

The Promise of Spring

The grey days of January can be a discouraging time for the gardener.  The once bright and crisp leaves of fall have faded to brown and lie crushed and torn on the ground, belittled by winter rains, freezing temperatures, and time itself.  Deciduous tree limbs are bare, and perennial flower stalks rattle in the wind, their seeds mostly gone now.  Native plants need this time to develop their roots and resources.  But in Georgia, if we look hard enough, we can still spot the promise of spring.

Hepatica nobilis var. obtusa

Last weekend I spied my first Hepatica americana bloom (now Hepatica nobilis var. obtusa) – right on schedule.  I was sorry to note that this was the second bloom, the first had already faded and was forming a seed capsule.  I went walking to see what else I could find.
Antennaria plantaginifolia

As my feet moved along the path, the decomposing leaves fluttered to the side, revealing the grey-green foliage of Pussytoes (Antennaria plantaginifolia).  These and other semi-evergreen plants like fairywand (Chamaelirium luteum) and green and gold (Chrysogonum virginianum) patiently tolerate the loose leaf cover; if you look closely, you can see the buds of new leaves already formed, waiting for the longer days and warmth of spring.

Evergreen gingers like Heartleaf (Hexastylis arifolia) and Shuttleworth (H. shuttleworthii) are getting the last bit of use out of their leaves. New leaves will replace these fading ones which are a bit tattered and droopy now.  As spring gets closer, sometimes I pull away the leaf duff to see if the flowers are visible yet. It’s a demonstration of my impatience – I love the hidden flowers of our native gingers. Perhaps I should keep a journal to remember which day they will bloom.

Hexastylis arifolia

As I make my way around the back of the house I notice that elderberry leaves (Sambucus nigra ssp. canadensis) are emerging already along the pale stems.  One of my St. John’s wort species also has tiny new leaves already. The blue-green foliage of the columbine (Aquilegia canadensis) soaks up the sun; it never really disappears either.  Above it, the flower buds on the blueberries (Vaccinium sp.) are plump in expectation of flowering in the next month or so; their flowers are some of the earliest, timed to nourish the bumblebees emerging from hibernation.

Blueberry, Vaccinium sp.

I see the berries are ripening on the wax myrtle (Morella cerifera) – turning a beautiful shade of blue-grey. Juniper berries (Juniperus virginiana) are ready for the birds that love them - birds like cedar waxwings, bluebirds, and robins.  And while I was looking at the berries, I saw that the new cones are forming on the juniper, no different than the flower buds already waiting on the tips of the dogwood (Cornus florida) branches.

Berries on Morella cerifera

New cones on Juniperus virginiana

And on the deck, stashed in rows of 1 gallon pots, is one of my favorite promises: the tender foliage emerging from the seed of a red buckeye, Aesculus pavia.  Yes, spring is on the way, but it does need every moment of winter to get ready for it -- I'll wait right here.

Seedling Aesculus pavia

Sunday, January 15, 2012

Native Evergreen Conifers in North Georgia

As a companion piece to my posts last year on Winter Twigs and Leaf Identification, this post gives some tips for learning how to identify some of the more common native evergreen conifers that grow in north Georgia.  As you may know, not all evergreens are conifers (think of hollies and rhododendrons), and not all conifers are evergreen (think of bald cypress). But since most conifers ARE evergreen, we've got a few things to work with here.

Blue-green foliage of white pine

Tsuga, hemlock

In the great kingdom of Plantae, conifers in Georgia are found in the Division Coniferophyta, in the Class Pinopsida, and in the Order Pinales, which has five families.  And within the Pinales Order, only two families are represented in Georgia: Cupressaceae and Pinaceae.  That is to say, there aren’t many conifer families in Georgia!  Of note: we are just outside the natural range of Abies (fir) and Thuja (arborvitae).

Tsuga canadensis foliage
The Pinaceae family is where most of Georgia’s evergreen conifers reside yet it is represented by just 2 out of the nine genera here: Pinus and TsugaTsuga, known as hemlock, has two species: Tsuga canadensis is more prevalent than Tsuga caroliniana.  Hemlock is very shade tolerant and is generally found in mountain communities, but it does fairly well in gardens as well.

Hemlock is easily noted by its flattened, short needles; it's graceful, drooping form; and by the tiny, flexible cones it produces. The needles are single and are two-ranked along the stem, meaning they reside in a horizontal plane.

Pines have round needles that surround the stem (not two-ranked), often lose their lower branches over time, and have stiff cones that sometimes have prickles.  The needles are arranged in bundles along the stem.

With the common pines of north Georgia I find that looking at the needles is the quickest way to make an identification.  If you were to look at a list of the pines (Pinus spp.) that are native to Georgia, this might seem a little daunting. But if you live in north Georgia like I do, there are really only four and, with just a little help, I think you can learn to tell them apart.  If you live elsewhere, perhaps you can pick some tips on how to identify them in general.

The four pines that you are likely to find in north Georgia are: Pinus echinata (shortleaf pine), Pinus strobus (eastern white pine), Pinus taeda (loblolly pine), and Pinus virginiana (Virginia pine).  The needles are arranged in bundles within a fascicle at the base of a bundle, so you need to examine how many there are, how long they are, and if they are straight or twisted.

From top to bottom, the picture above shows:

loblolly (usually 3 needles per bundle, length is 5-8 inches); 
eastern white pine (5 needles per bundle, color is bluish-green); 
shortleaf pine (2-3 needles per bundle, length is 3-4 inches); 
Virginia pine (2 needles per bundle, needles are short and twisted).

Below are some pictures of the cones:
Pinus taeda: large cones with prickles

Pinus strobus: long cones, no prickles

Pinus echinata, short cones stay on
tree; small prickle

Pinus virginiana, short cones stay on
tree but prickle is long and sharp

White pine branches

White pine does have one interesting growth characteristic - the branches tend to encircle the tree, like spokes on a wheel. So, if the branches are intact, you might be able to confirm it by looking at the trunk.

By the way, pines do lose their leaves (that is, their needles), just not all at once.  The loblolly pines in my yard drop some needles in the fall, about the same time that deciduous trees are dropping theirs too.

The Cupressaceae family is represented by 3 genera in Georgia: Chamaecyparis, Juniperus, and TaxodiumTaxodium, a genus perhaps most familiar to people by the species Taxodium distichum (bald cypress), will not be covered here because it is deciduous (a trivia question for your family: "Name a deciduous conifer"). Chamaecyparis is represented in Georgia by Chamaecyparis thyoides (Atlantic white cedar) but that is not indigenous to north Georgia (although people do grow it here). That leaves us with Juniperus virginiana which is found throughout Georgia; however, it is best known by its common name, eastern redcedar.  People are often surprised when you tell them it is a juniper.

I learned something when I was researching Juniperus virginiana for this article.  I was certainly familiar with the plant - it grows everywhere around here, and I've dug up many a small one. However, I had not seen one with fruit so I decided to try and find one.  I looked at a lot of trees before I found one, but I was puzzled when I did.  The foliage didn't look right.  As I dug into my references a little deeper, I found the answer.  The mature foliage is different!  Juvenile foliage is needle-like and prickly - what I was used to seeing; the mature foliage is "awl-like" and scaly with overlapping sections - not prickly.

Berries and mature foliage, Juniperus virginiana
Juvenile foliage, Juniperus virginiana

It is also curious to think that junipers have berries - why would a conifer have berries instead of cones?  Well, the "berries" are actually cones with fleshy scales that have fused together, creating the appearance of a berry.

So now that you know a little bit more about identifying these plants, spend some time outside practicing your identification skills.  Those fragrant green trees with needles are not all alike; the differences are there for you to discover.

Good tree identification references for the southeastern U.S.:

Native Trees of the Southeast: An Identification Guide by Kirkman, Brown and Leopold
Woody Plants of the Southeastern United States by Ron Lance
Guide to Southern Trees by Harrar and Harrar (Dover publication) – you can get this used on Amazon for as little as $1.50 plus shipping; it’s a great starter for young people and the line drawings are excellent.

Sunday, January 8, 2012

Frost Flowers

I had a chance this week to find something quite unusual in my yard - frost flowers.  They are not true flowers, and it takes a special event in Georgia to produce them: good moisture in the ground and it's got to get COLD.  I like the explanation in Wikipedia so much that I will paste it here verbatim:

"The formation of frost flowers, also known as "ice flowers," is dependent on a freezing weather condition occurring when the ground is not already frozen. The sap in the stem of the plants will expand (water expands when frozen), causing long, thin cracks to form along the length of the stem. Water is then drawn through these cracks via capillary action and freezes upon contact with the air. As more water is drawn through the cracks it pushes the thin ice layers further from the stem, causing a thin "petal" to form."

Late summer flowers, Cunila origanoides

I learned about this condition only recently by way of a friend in the Georgia Native Plant Society.  She called it "crystallofolia" and provided some pictures of dittany (Cunila origanoides) in her yard exhibiting the condition.  Another friend used those pictures to write an article about it for the January newsletter.  Still - I didn't expect to see it myself.  We've had some warm weather lately but earlier this week it got very cold - below 20 overnight!

After a tip from my friend Jane that she found some in her yard, I went outside to look. Bingo!  My dittany had frost flowers too!

While this oozing, freezing, "flowering" event is very exciting, photographing it is so not easy!  Here is a picture of the frost flowers in my yard:

Cunila origanoides

A much better picture belongs to my friend Jane - she sent me this picture of the frost flowers on her Joe-Pye weed (Eupatorium sp.):

Eupatorium sp.

This subject is a popular topic this week due to the cold snap throughout the eastern U.S. Gail over at the blog Clay and Limestone also has a post on this with some very excellent pictures of Verbesina virginica from Tennessee.

Sunday, January 1, 2012

Birds Love a Thicket

I walked past a grassy strip the other day and a flock of small birds rose up from where they had been feeding on small seeds and insects.  Anxious to escape whatever harm might befall them, they headed for a nearby thicket of dense shrubs.  The twiggy growth of the thicket was the perfect protection from any dog, cat or large bird that might have been chasing them.  Nature has always created such thickets - perhaps it is time that we consider how they might be part of our own landscape plan.

Cardinal in shrubbery - looks like he feels safe!

R K Young at Native Backyard recently shared an article from Audubon magazine about supporting birds that migrate. One point the author makes is how the different migrating birds rely on various vertical layers in the wild.  However, one layer is often missing in suburban landscapes:  the layer composed of shrubs and small trees.  The article recommends that we: "Fill in the gaps with shrubs, the more different types the better. Many migrants are attracted to thickets, dense masses of fruiting shrubs, vines, briers, and brambles."

Sparkleberry (Vaccinium arboreum) with grape vine and fence
makes for a good hedge
A hedge (or hedgerow) might be another way to consider the concept of a thicket.  Hedges are typically a densely grouped area of medium to large-sized shrubs.  While many people use them for privacy or to define a property boundary, they can also be used to create rooms within a large garden space or, in this case, provide a place for shelter for small birds.  I have some evergreen shrubs near my birdbath and the birds often land there first to make sure the area is clear of predators before flying in to get a drink or a bath.

Once you decide on a purpose for your thicket (privacy, boundary, or just for wildlife?) and a location for it in your yard, it’s time to consider what plants could be used to construct it.  Consider the following points:

-          Height: Does the planting need to be kept to a certain height or can you accommodate a variety of heights in the group?  If there is a certain height, be sure to consider the mature height of the chosen plants so that you are not required to prune to stay within that height.  Well, unless you LIKE to prune, of course.

-          Light exposure: How much sun does the area receive?  If more than 6 hours per day or if it is in the hot afternoon summer sun, then full sun plants should be chosen.

-          Appearance: What is the desired overall look?  Use all one type of plant for a more formal look, or use a mixture of plants for an informal look (or especially if you have a hard time choosing just one type of plant!). Evergreen or deciduous?  Personally, I prefer a mixture – deciduous plants tend to give you more blooms but evergreen plants will give you some year-round greenery.

Once you’ve answered those questions for yourself, you can make your choices. Dense, twiggy shrubs are the best - if the limbs have small thorns, all the better. Such plants allow small birds to fly in while making it more difficult for large predators to follow. You can improve the denseness by selective pruning. You may have noticed before that when you prune a twig, new growth is often produced in multiple shoots. That is, for each cut, 2 or 3 new shoots appear.

Here are some ideas for evergreen plants that might be used for hedges/thickets in north Georgia:

Hobblebush (Agarista populifolia, used to be Leucothoe populifolia), 8-12 feet
Doghobble (Leucothoe fontanesiana), up to 5 feet (L. axillaris is similar)
Inkberry (Ilex glabra) - can handle moist conditions
Florida Anise (Illicium floridanum) – part shade; I. parviflorum is bigger and more sun tolerant.
Rhododendron maximum or R. catawbiense - need afternoon shade
Mountain laurel (Kalmia latifolia) - afternoon shade
Eastern redcedar (Juniperus virginiana), over 30 feet
Wax myrtle (Morella cerifera, used to be Myrica cerifera), 15-20 feet
Yaupon holly (Ilex vomitoria), 15-20 feet

Mountain laurel (Kalmia latifolia) mixed with small trees

Dwarf forms of some of the above:

Agarista populifolia ‘Leprechaun’
Ilex glabra ‘Compacta’ up to 6 feet
Ilex glabra ‘Shamrock’, slowly growing to 5 feet
Morella cerifera ‘Don’s Dwarf’, ‘Fairfax’, both up to 6 feet
Morella cerifera ‘Suwanee Elf’,  up to 4 feet
Kalmia latifolia ‘Elf’, ‘Minuet’ and others
Ilex vomitoria ‘Nana’ (male plant, no berries)
Ilex vomitoria ‘Schillings Dwarf’ or ‘Stokes dwarf’

Here are some ideas for deciduous plants that might be used:

Hawthorns (Crataegus spp.) - small to medium tree to anchor the hedge
Serviceberry (Amelanchier spp.) - small to medium tree, 15-30 feet if A. arborea
Sparkleberry (Vaccinium arboreum)  – large shrub, small tree, up to 12 feet (slowly)
Viburnums (especially V. prunifolium and V. rufidulum), up to 12 feet (slowly)
Winterberry (Ilex verticillata) - good in a moist area
Fothergilla (Fothergilla major or F. gardenii)
Summersweet (Clethra alnifolia) - good in a moist area, use cultivar 'Hummingbird' for low growth

Passiflora incarnata

Remember that a variety of plants will support more wildlife through diversity.  Also, consider adding a vine or two to increase the complexity of the thicket: a fast and showy grower would be Passionflower (Passiflora incarnata); the native Honeysuckle (Lonicera sempervirens) would add some bright color in a sunny hedge; one of the leatherflower Clematis (Clematis viorna perhaps) would have unusual blooms and seedheads.

Remember that many of these plants are host plants for certain insects (which the birds eat) and many of these plants have berries or seeds that the birds eat.  You can't help but benefit the birds in several ways with most of these choices.